Fully transparent parts count as unique entities, resulting in games with large amounts of fully transparent parts having inflated entity counts. We expect fully transparent parts to be ignored completely by rendering. This probably impacts performance if fully transparent parts are being submitted to the GPU.
Repro:
Insert a part into studio
Open the Graphics Stats menu (Shift + F2 or Ctrl + Shift + F2)
Notice how the draw call count increased when you selected the objects? The extra draw calls you’re seeing here are all thanks to the selection.
If you have outline based selection on: If you select an object it now has to be rendered to the objectId layer used to compute the outlines, including the selection outline.
If you have bounding box outlines on: The object bounding boxes have to be rendered.
If you deselect them you should no longer see the draw call count be elevated even with a bunch of invisible objects.
This only happens if you have your Selection Style set to Outlines. I use Bounding Boxes in the video, which does not add to the entity count. If you watch the video again, you will notice that when I duplicate parts (Ctrl + D) it deselects the old selection in favor of the newly duplicated parts.
Here is another video demonstrating this if the first one wasn’t clear enough:
In the video at 39 seconds, you can see that with none of the (many) invisible parts selected, the draw call count is back down at 23 like it was at the start.